1. Technical Field
The present disclosure relates to a lug, for a lithium ion battery, with a positive temperature coefficient (PTC) layer.
2. Description of Related Art
A lithium ion battery is normally provided with a battery protection device to prevent overcharging and over discharging. Such a battery protection device is generally unitized with the lithium ion battery as part of battery pack configuration, in which a circuit board that makes up the battery protection device is integrally contained in the pack case along with the lithium ion battery. It is common knowledge that battery packs such as this, are often used for battery-powered devices such as cell phones and laptops.
In addition to prevent overcharging and over discharging as mentioned above, this battery protection device can also have such functions as cutting off excessive current or monitoring cell temperature. If this device could be integrated with the lithium ion battery itself, it would be possible to create a lithium ion battery equipped with a battery protection device without constituting a battery pack, which would make the lithium ion battery more universally applicable.
When a battery protection device is integrated with a lithium ion battery, however, it is difficult to avoid making the external dimensions larger or losing the original configuration of the lithium ion battery. In particular, a flat-shaped lithium ion battery is made thin so that it can be used in small devices. Furthermore, when a battery protection device is integrated with such a lithium ion battery, it is difficult to find space for the circuit board that makes up the battery protection device. Thus, it is difficult to integrate a battery protection device without increasing the external dimensions.
Although the art has made strides toward minimizing the increase in the external dimensions of the lithium ion battery, there remains a need for a compact lithium ion battery that can be widely applied and safely operated.